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Both osmosis and diffusion are passive processes which move a substance from an area of high concentration to low concentration. Osmosis is the movement of _____ and diffusion is the movement of _____ across a membrane.

What is the organelle at D on this animal cell?   

During transcription the DNA base sequence is transcribed into a complementary mRNA sequence. A codon table like the one shown below lists the amino acids coded for by particular triads of mRNA bases. A segment of DNA has undergone a mutation in which one nucleotide has been changed. The original codon resulting from the original DNA sequence was UUA and the new codon sequence is CUG. Use the codon table to determine whether or not this mutation will cause a change in the phenotype of the organism.  

The diagram below represents a cell in a solution. The solute molecules are represented by the yellow larger dots, the water molecules are represented by the smaller blue dots. Explain why more water is moving out of the cell than into the cell.  

Which process can alter a plant to become resistant to pests?

Your backyard represents a(n) _______ while the crickets in the backyard represent a(n) ______.

Which of the following statements is a principle of the cell theory that supports the idea that new cells will replace damaged cells in a scraped knee?

Which of the following levels of organization is arranged in the correct sequence, from most to least inclusive?

Some cells in the body turn over rapidly. Skin cells constantly bubble up from stem cells in the dermis and blood cells are continuously produced in bone marrow. Other cells live a long time without duplicating, such as most neurons and cells forming the lens of the eye. If all cells lived a uniform medium time span, what consequences might you predict?

The diagram below illustrates a biochemical process that occurs in organisms. What is another name for the substance labeled “catalyst”?